LG 700E monitor dead

October 30, 2011 at 10:46:47
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monitor dead power led dsnt light up only very faint tick tick sound

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#1
October 30, 2011 at 11:19:48
Update - apparently your monitor model is a CRT monitor, not an LCD monitor model.

If it's had more than 5 years of use, or in any case , I recommend you throw it away. If it doesn't have the problem I mentioned below, it's probably reached the end of it's life, and you may not be able to get replacement parts anymore in any case. If you heard a loud buzzing or the sound of electrical arcing before it failed completely it probably cannot be fixed without you spending more money on it than it's worth !

If you DO open it up NOTE that the outside of the back of the tube / inner outside surface of the back of the tube have coatings that make it essentially a huge capacitor, connected via a large cable to the fly back transformer. The HIGH VOLTAGE charge stored by the outside surfaces of tube is often retained for a LONG time after the power to the CRT monitor has been removed ! DO NOT mess with, or try to clean the crap off, that large cable or it's connection to the tube under the large rubber grommet, or touch anything connected to that large cable or anything in the fly back transformer the cable connects to ! You can receive a LARGE HIGH VOLTAGE (up to 20,000 volts) electrical SHOCK if you do ! The CRT monitor was probably designed so that doesn't have enough current to kill you if you're healthy, but it's enough of a jolt that you may temporally lose control over your muscles causing your hand or arm or body to jerk away and you possibly injuring yourself !
It's like the electrical jolt you get from a spark plug wire on a car when the car is running, if you've ever experienced that, but possibly stronger than that !
Do not touch anything inside the case with both bare hands - if that charge discharges it won't likely go across your chest and possibly affect your heart if you do that.
Don't open it up at all if you have heart problems and/or have a pacemaker !!
If you use anything to insulate your hands, it must be able to withstand up to a 20,000 volt discharge !

I prefer CRT monitors and I'm going to continue to use them as long as possible.
If you prefer CRT monitors, you can usually find them used locally for a cheap price or for free.
Or buy yourself a new or used LCD or LED LCD monitor - the smaller new models are inexpensive - the new LED LCD monitors will produce a usable display for a lot longer, in theory, than new LCD monitors, and if you buy a used LCD monitor it will produce a usable display for a shorter time than a new LCD monitor will.

If you have a choice of more than one used monitor you can examine, look on the back of it - the date it was manufactured is often there somewhere - the newer it is, the more likely it will have a usable display for a longer time.
............

If you're handy, you could open it up to see if there is anything obvious you may be able to fix.

If you're not, you could take it to a local place that is authorized tor repair LG models or any place that repairs laptops and have them do that.
Note - many places no longer repair CRT monitors.


NOTE - this is about an LCD model.

A friend of mine has an older LG model that eventually stopped producing video, but the power led still lit up.
Out of curiosity I took it apart to see if I could find anything obvious I could fix

On one of the two circuit boards inside of it, It had one failed electrolytic capacitor, and one more that hadn't failed yet made by the same maker.
I replaced both of those capacitors with high quality ones I got locally from an electronics parts place whose owner used to repair desktop mboards (less than $20), and that monitor has worked fine ever since.
(It's recommended you replace all electrolytic capacitors made by the same manufacturer as any that failed that are not really tiny, because they're just as likely to fail.)

If you do take it apart yourself,.....
- note that you usually have to use something metal that's at least a 1//2 inch wide (to avoid damage) and very thin between the edges of at least some the case pieces after you have removed all screws to un-latch internal plastic latches on one side that are hooked into plastic catches on the other side that are holding the pieces together.
- you may need to carefully unplug wiring connectors before you can separate the pieces completely. .
- if any wiring connectors are identical, mark or tag them to make sure you plug them into the right places, however they may only go in one place due to the length of the wires they connect to.
- be careful.

The following is about defective capacitors on mboards, but it also applies to anything electrolytic capacitors were used on - power supply boards, computer cards, monitor boards, whatever.

Some mboards develop this problem - electrolytic capacitors were installed on them that were not properly made, and they fail eventually - the mboard manufacturer didn't know they were improperly made at the time the mboard was made.

Open up your case and examine the mboard to see if you have bad capacitors, and/or other findable signs of mboard damage .

What to look for, mboard symptoms, example pictures:
http://www.badcaps.net/pages.php?vid=5
Home page that site
- what the problem is caused by
- he says there are STILL bad capacitors on more recent mboards.
http://www.badcaps.net/

Pictures of blown capacitors, other components, power supplies, fried Athlon cpus, etc.:
http://www.halfdone.com/Personal/Jo...



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#2
October 30, 2011 at 18:35:57
first of awl thanx for replying..Its an 8 year old CRT and as far the safety hazards goes dont worry I know them and dats y I didnt tried to be a Hero. The reason I posted my query is because the technician told me(without even checking anything) that the EHT is faulty whereas as far my knowledge goes even if the EHT is damaged still the power lED should glow up. But he was lyk the power supply is OK and the tic tic sound is produced by safety circuit (dont knw wht does it mean). So my point of asking is if its confirmed that the EHT is messed up or the cap or fuse or diode of power supply is the real culprit.
P.s. Even I like CRTs more than anything.
P.p.s thanks for showing interestd in this topic :)

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#3
October 30, 2011 at 18:56:55
I forgot to mention some very important facts though. a month back my screen flickered as in the whole screen collapsed horizontally and got restored back within milli seconds..it used to happen once in 3 or 4 days since last month and last tym my monitor worked the whole screen got stretched horizontally and the front panel control couldnt correct it. So I switched off my monitor after which it never even turned ON. I m planning to buy an lcd led now in case my CRT couldnt get repaired.

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Related Solutions

#4
October 30, 2011 at 19:38:52
The only way you're going to possibly find out for sure is to open up the case, and what is wrong is often NOT obvious, I've looked at the insides of many things that have failed and usually it is NOT obvious what is wrong. The technician would likely have a good idea what to replace if he saw what's inside it, or he may need to run a test or tests, if he has worked on a lot of monitors. You could replace what he says to replace, if the pieces are still available and not too expensive, if you have decent soldering skills, unless it's a zillion pronged or surface mounted IC, which he would likely have the proper equipment to properly replace.

Some CRT monitors have relays that cause the display to briefly disappear while booting or loading the operating system, but that would have happened since it was new and you probably would have heard a clicking sound when it did that.

It sounds like something related to the high voltage circuitry or the fly back (a.k.a. flyback) (high voltage) transformer was failing.

If I were you I would move on to another monitor. 8 years is very good for the useful life of a CRT monitor.

I had a 15" Mitsubishi Diamond Scan that lasted 12 or so years, until late 2009 ? (maybe more - I bought it in 98, or earlier ? ) - the brightness was still good just before it failed - not set to the max to produce a bright enough display like many old CRT monitors. Then it started making horrible loud arcing sounds - I opened it up and took a look - nothing obvious - it died completely a day later.

My newest one is an AOC 17", the one I use with this computer is next newest, a Samsung SyncMaster 17" - 763MB. I have several older ones.

I completed a 3 year electronics course in high school with good grades, but that was way back in 67-69. We were more likely to repair things with vacuum tubes in them than newer things with discrete transistors etc, if we had become a technician back then.
Graduating from the course took one year off a 3 year electronics technician course in several government technical schools, but I didn't got for it.

The flyback transformers for CRT TVs were deliberately designed so they couldnt produce enough current to kill a healthy person, and the same probably applied when you accidently discharged the outsides of the tube. That's probably the same situation for CRT computer monitors.

The same applies for vehicle ignition systems.

ICs were a brand new thing. Personal computers didn't exist. We learned about CRT TVs - CRT monitors are similar.
I have only examined the insides of 3 or 4 CRT monitors, one LCD monitor.


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#5
November 6, 2011 at 08:10:53
I finally bought an LG FLATRON E2290V and m quite impressed with its performance :)

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#6
November 6, 2011 at 08:36:05
We're glad to hear you found an LCD monitor solution

However, if you bought it new, an LED LCD model rather than an LCD model will produce a useful display for a lot longer in theory - it may never stop producing a useful display.


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#7
November 6, 2011 at 08:44:47
yeah its a Super LED LCD display

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#8
November 6, 2011 at 11:38:29
Alright !
The "hits" I looked at before didn't mention it was LED backlit.

It has a good 5ms rating, but the vertical refresh rate is the bottom end - 60 Hz.

Apparently the LG 700E was a modest model

Horizontal: 30 - 70 KHz
Vertical: 50 - 160 Hz

Maximum Resolution 1280 x 1024 @ 60 Hz

If you were using it at the max resolution you won't see much difference.

However if you were using it at a lower resolution, the possible vertical refresh rate could have been set a lot higher than 60 Hz, and in that case, motion (e.g. in games, videos, DVD playback) on the 700E would have looked better than it will on the E2290V, especially horizontal motion.

I always set my vertical refresh rate for CRT monitors to the max the specific model can be set to for the resolution I'm using.
....

I recommend that you install the specific monitor drivers for your model.

See response 9 here for XP:
http://www.computing.net/answers/ha...
...

Vista / Windows 7

RIGHT click on a blank area of the main desktop screen, choose Properties - Personalize - Display Settings - Advanced Settings - Monitor - Properties - Driver - Update Driver - Browse my computer.... - Let me pick from a list... - Next -
If you have the CD that came with the monitor that has the specific drivers for the monitor, or a download that has the specific drivers for the model, click on Have disk lower right, Next, and go to where the drivers are - Windows is looking for an *.inf file. (NOTE that if the monitor is LCD or Plasma, you should load the specific drivers if they are available, because you can choose settings in Generic PNP Monitor mode that can DAMAGE the monitor ! )
If you chose specific drivers, if there is a list of models, choose the correct one, etc.
click on Close on the Driver window.
click on OK on the Monitor window.
click on OK on the Display Settings Window
close the Personalize window.


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#9
November 6, 2011 at 20:48:16
it has a 2ms response time and a 10 mega contrast ratio and a max resolution of 1920x1080 ..Here is the link about the product
www.lg.com/in/computer-products/led-monitor/LG-E2290V.jsp
thanks alot for showing interest in my posts and for your guidance..

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